how to match the String... use Mockito and PowerMock

Question

I am studying Mockito and PowerMock recently.

I ran into the following problem

    //This method belongs to the Messages class
    public static String get(Locale locale, String key, String... args) {
        return MessageSupplier.getMessage(locale, key, args);
    }
    //the new class
    @RunWith(PowerMockRunner.class)
    @PowerMockIgnore( {"javax.management.*"})
    @PrepareForTest({Messages.class, LocaleContextHolder.class})
    public class DiscreT {

        @Test
        public void foo() {

            PowerMockito.mockStatic(LocaleContextHolder.class);
            when(LocaleContextHolder.getLocale()).thenReturn(Locale.ENGLISH);

            PowerMockito.mockStatic(Messages.class);
            when(Messages.get(Mockito.any(Locale.class),Mockito.anyString(), Mockito.any(String[].class)))
                    .thenReturn("123156458");

            System.out.print(Messages.get(LocaleContextHolder.getLocale(), "p1"));

            System.out.print(Messages.get(LocaleContextHolder.getLocale(), "p1", "p2"));

        }
    }

the result : null 123156458

why? and how to match the String...

Answer 1

In your first System.out.print statement, you use 2 arguments for the Messages.get method. This is one of the method's overloads that you have not mocked. That's why it returns null. Note that object mocks that have not had their behavior mocked will return null by default.

You would have to mock the Messages.get(Locale, String) method as well if you want it to work

when(Messages.get(Mockito.any(Locale.class),Mockito.anyString()))
                    .thenReturn("123156458");

Remember, the fact that you have mocked the method that takes the most arguments doesn't mean Mockito understands and mocks the rest of the overloads! You have to mock them as well.

There is no way to mock a method once and automatically mock all of its overloads as far as I know however, there is a way to create a mock object and configure a default response for all of its methods. Check out http://www.baeldung.com/mockito-mock-methods#answer